Electronic wrist watches having a digital display may employ active or passive display means. Watches having active display means such as light emitting diodes normally display watch functions only upon command in order to conserve the power required for display. Such commands are conventionally provided by a push button extending through the watch case. Watches having passive display means such as liquid crystals continuously display watch functions and may be provided with a push button for changing the functions displayed.
Early digital watches employed what may be termed a logic state switching system for adjusting or setting the watch. Thus, for a watch adapted to display hours, minutes and seconds, activation of a first switch set the hours, activation of the first switch and second switch together set the minutes and activation of the second switch alone maintained the display at zero seconds for time synchronization. This system has been quite satisfactory; however, any attempt to increase the watch functions to be displayed causes a number of difficulties. It is possible to employ a three button system to set up seven functions in a logic state switching system; however, the various combinations and permutations of a non-simultaneous activation of these switches cause the setting operation to be quite complicated and error prone.
An alternative method or system for the display and setting of digital watches provides a sequential operation. Thus, for example, a first switch may be employed to put the watch into various setting modes in sequence while another switch is then employed for adjusting the readout in the set mode.
The present invention provides a system and method of digitally displaying watch functions and setting or adjusting such display with only a single actuator or switch. The present invention materially simplifies adjusting operations by the user of a digital watch and simplifies construction of such a watch with a consequent reduction in size, which is especially important for ladies watches. The invention furthermore reduces the cost of electronic watches.